Birth-weight patterns in aboriginal and non-aboriginal singleton adolescent births in Western Australia, 1979-83.

Births to Aborigines and teenagers are known to be at a higher risk of low birth-weight (LBW) than those to non-Aboriginal and older women. Data on singleton birth-weight and gestational age by maternal age and race were analysed from the West Australian Midwives Notification of Birth system for 1979-1983. The main aim of the analysis was to describe the patterns of preterm birth (PTB) and intrauterine growth retardation (IUGR) in these births. Aboriginal teenage fertility was much higher than that for non-Aborigines and seemed to be rising. Many more young teenagers giving birth were Aboriginal than Caucasian. Contrary to expectation, the majority of the LBW births in both racial groups were due to PTB not IUGR. There was an increasing trend to PTB with decreasing maternal age in both Aborigines and non-Aborigines. These data should be considered preliminary due to the difficulties of estimating gestational age and in categorizing IUGR. They may have implications in terms of further research into the aetiological pathways and prevention of LBW in Australia.